JP2006196830A - Surface luminescence semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high performance surface luminescence semiconductor device that has good characteristics in polarization mode control and mass productivity even at fabrication on regular boards such as plane direction (100) plane. <P>SOLUTION: This semiconductor device comprises a semiconductor active layer 4 with a luminescence area, a first semiconductor multi-layer mirror reflector 6 and a second semiconductor multi-layer mirror reflector 2 which form a vertical resonator, electrodes 9 and 10 for flowing current into the semiconductor active layer, first oxidized layers 32 and 30 with Al which are formed near the semiconductor active layer, a current narrowed portion where the side of the first oxide layer is oxidized but the center is not oxidized, a first concave 12a with a channel depth at least up to the top surface of the first oxidized layer, a second concave 12b penetrating the first oxidized layer, a mesa 100 surrounded by the first and second concaves, and an insulated film 200 embedded at least in the second concave of the first and second concaves. In addition, the first oxidized layer has different size of oxidized areas in directions where the first and second concave have been created. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a surface emitting semiconductor element.

  Semiconductor light emitting devices such as semiconductor lasers and semiconductor light emitting diodes are widely used in optical communication fields, optical disc systems such as CD (Compact Disc) and DVD (Digital Versatile Disc), or barcode readers. When used in various application fields such as optical communications, the operation mode must be unified for the three modes of the “longitudinal mode”, “lateral mode”, and “polarization mode” that exist in semiconductor lasers. Is important. At present, the edge-emitting semiconductor laser mainly used in the field of optical communication has a stable polarization mode and does not fluctuate. This is because, in the case of an edge-emitting semiconductor laser, the resonator is composed of a waveguide, the reflectivity of the waveguide end face is larger for the TE (Transverse Electric) wave than for the TM (Transverse Magnetic) wave, and the electric field vector is the semiconductor substrate. Oscillates with a TE wave in a direction parallel to. The longitudinal mode can also be unified by adopting a distributed feedback structure or the like, and the lateral mode can also be unified in the edge emitting semiconductor laser by adopting a narrow stripe structure.

  On the other hand, in the case of a surface emitting semiconductor laser, since the resonator is very short, the longitudinal mode operates in a single mode, and in the transverse mode, the current due to selective oxidation of aluminum (Al) high-concentration layer or proton injection Due to the constriction structure, single mode operation has become possible by techniques such as miniaturization of the active region.

  However, in the polarization mode, it is difficult to control the polarization direction as compared with the edge-emitting semiconductor laser. This is based on the symmetry of the crystal structure of the (100) plane substrate and the device structure itself that have been used in the manufacture of ordinary surface-emitting semiconductor lasers. This is because there is no gain difference between orthogonally polarized waves, and measures such as increasing the reflectivity of the reflecting mirror with respect to polarized waves in a specific direction are difficult. For this reason, due to subtle changes in external conditions such as temperature and driving current, switching in the polarization direction is easily caused, which has a great influence on magneto-optical recording or coherent communication using the laser polarization directly. Even when performing normal data communication, the instability of the polarization mode causes excessive noise and mode contention, causing problems such as an increase in errors and a limitation on the transmission band. For this reason, the control (stabilization) of the polarization mode is one of the important issues in the actual application of the surface emitting semiconductor laser.

  In order to solve this problem since the importance of polarization control was pointed out, the following methods have been introduced.

(1) Structure in which a metal dielectric diffraction grating is incorporated in a reflector made of a semiconductor multilayer film (2) Structure in which asymmetry is incorporated in the mesa shape of the device (3) Fabrication on an inclined substrate (4) Part of the resonator A structure in which an insulating layer is provided so as to come into contact with the outer surface of a columnar portion. Among these four methods, the method (1) is a method in which fine metal wires are arranged in a fixed direction on a reflector made of a semiconductor multilayer film. This is a method for increasing the reflectance of a mirror with respect to polarized light in a specific direction. Since the reflectivity of the mirror is high for polarized light parallel to the metal wiring, there is a certain effect in stabilizing the polarization plane, but it is necessary to form the metal wiring with a width less than the light wavelength, Manufacturing is difficult.

  In addition, as a method for incorporating asymmetry in the mesa shape of the device (2), it is disclosed in Patent Document 1 as an example. In Patent Document 1, by providing a stress applying region in the mesa periphery, stress is applied anisotropically (anisotropically) to the active layer at the center of the mesa, and strain is generated anisotropically. A gain difference between orthogonally polarized waves is caused by such distortion, and only polarized waves in a specific direction are dominant, and polarization controllability is improved.

Similarly, also in Non-Patent Document 1, a T-shaped protrusion shape is added to a cylindrical mesa structure. As a result, the Al high-concentration layer (Al _0.9 Ga _0.1 As layer) of the reflector composed of the semiconductor multilayer film in the T-shaped thin line portion is entirely oxidized by the selective oxidation process, and is generated as the volume shrinks. The strong stress exerts anisotropic strain on the active layer located at the center of the mesa, thereby improving the polarization controllability.

Further, in Non-Patent Document 2, polarization control is achieved by using a dumbbell mesa structure so that current injection into the active layer becomes asymmetric. These stress (strain) applied regions and asymmetrical mesa structures, like (1) described above, have a problem in that device processing is complicated, and element productivity, reproducibility, and polarization controllability are not sufficient. is there.
On the other hand, in the method using the tilted substrate of (3), the active layer is formed on the high index orientation crystal plane such as the (311) A plane or the (311) B plane in order to increase the gain with respect to the polarization of a certain orientation. And the fact that the gain depends on the crystal orientation is used. In this method, a strong extinction ratio between orthogonal polarizations is obtained, and the controllability of the polarization mode is excellent. However, there are problems such as that it is difficult to grow a high-quality crystal and it is difficult to obtain a high output as compared with those using a normal (100) plane. In addition, in a selective oxidation surface emitting semiconductor laser element on an inclined substrate, the oxidation (light emitting region) shape is distorted due to the difference in oxidation rate (anisotropic oxidation) depending on the crystal plane orientation, making it difficult to control the beam shape. It is.

  Moreover, although the structure which provides an insulating layer so that it may contact the outer surface of the columnar part of (4) is disclosed by patent document 2, the structure of this patent document 2 originates in the planar shape of an insulating layer. The polarization direction of the laser beam is controlled by the anisotropic stress. However, the control of the polarization direction of the laser beam is insufficient with only the stress caused by the planar shape of the insulating layer described in Patent Document 2.

Surface-emitting semiconductor lasers have lower thresholds, lower power consumption, higher emission efficiency, and higher-speed modulation, and beam divergence, compared to edge-emitting semiconductor lasers, except for polarization mode control issues It has a number of advantages such as being easy to couple with an optical fiber, having no cleaving at the end face, and being excellent in mass productivity. Furthermore, since a large number of laser elements can be integrated two-dimensionally on a substrate, it has attracted a great deal of attention as a key device in the field of optoelectronics such as a high-speed optical LAN (Local Area Network) and an optical interconnect. Accordingly, there is a strong demand for the development of a surface-emitting type semiconductor laser device that improves the current problems described above, polarization controllability, and is excellent in mass productivity.
JP-A-11-54838 IEEE Photon. Technol. Lett. Vol.14, no.8, 1034 (2002) IEEE Photon. Technol. Lett. Vol.6, no.1, 40 (1994) JP 2001-189525 A

  As described above, the surface emitting semiconductor laser device fabricated on a normal substrate such as the plane orientation (100) plane has a gain difference between orthogonal polarizations in the active layer due to the symmetry of the crystal structure. There is a problem that switching occurs easily and it is difficult to control the polarization mode.

  The present invention has been made in consideration of the above circumstances, and even when manufactured on a normal substrate such as a plane orientation (100) plane, the high-performance surface-emitting type that has high controllability and mass productivity of the polarization mode. An object is to provide a semiconductor device.

A surface-emitting type semiconductor device according to an aspect of the present invention includes a substrate, a semiconductor active layer having a light emitting region formed on the substrate, and the semiconductor active layer sandwiched between the substrate and a vertical resonance with respect to the substrate. A first semiconductor multilayer reflector formed on the opposite side of the substrate with respect to the semiconductor active layer and a second semiconductor multilayer reflector formed on the substrate side with respect to the semiconductor active layer. And a pair of electrodes for injecting current into the semiconductor active layer, and a first oxidizable layer containing Al formed in the vicinity of the semiconductor active layer, and a side portion of the first oxidizable layer is A current confinement portion that is oxidized and unoxidized at the center, a first recess having a groove depth that reaches at least the outermost surface layer of the first oxidizable layer, and a second recess that penetrates the first oxidizable layer; A mesa portion surrounded by the first and second recesses; An insulating film embedded in at least the second recess of the second recess,
The first oxidized layer of the current confinement portion is different in size of the oxidized region in the direction in which the first recess is provided and in the direction in which the second recess is provided. Features.

  The insulating film may also be embedded in the first recess.

  The first oxidizable layer may be formed on the substrate side with respect to the semiconductor active layer.

  The first oxidizable layer may be formed on the side opposite to the substrate with respect to the semiconductor active layer.

The current confinement portion may be formed on the substrate side with respect to the semiconductor active layer, and may include a second oxidized layer containing Al.
The second oxidized layer may be unoxidized at the center and oxidized at the side.

  The mesa portion may include a proton injection region in the first semiconductor multilayer mirror.

  In addition, it is preferable that the said insulating film consists of a material with a larger thermal expansion coefficient than the said board | substrate, the said 1st and 2nd semiconductor multilayer film reflective mirror, and the said semiconductor active layer.

  The insulating film may be made of a polyimide resin.

  The semiconductor active layer may be made of a semiconductor containing at least Ga, In, and one of As or N.

  In the present specification, the “oxidized layer” means a layer to be oxidized, and includes a state before being oxidized and a state after being oxidized.

  According to the present invention, a high-performance surface-emitting semiconductor element having high controllability and mass productivity of a polarization mode can be obtained even when manufactured on a normal substrate such as a plane orientation (100) plane.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
1 to 9 are schematic views showing the structure of a surface-emitting type semiconductor device according to a first embodiment of the present invention. 1 is a top view thereof, FIG. 2 is a sectional view taken along the cutting line AA ′ shown in FIG. 1, and FIG. 3 is a sectional view taken along the cutting line BB ′ shown in FIG. is there. FIG. 4 is a diagram showing the shape of the oxidized region 32a of the upper oxidizable layer 32 when the surface-emitting type semiconductor device of this embodiment is cut at a certain height 26, and FIG. 5 is a cut line AA ′ shown in FIG. FIG. 6 is a sectional view taken along the cutting line BB ′ shown in FIG. 4. 7 is a diagram showing the shape of the oxidized region of the lower layer to be oxidized 30 when the surface-emitting type semiconductor device of this embodiment is cut at another height 27, and FIG. 8 is a cut line A-- shown in FIG. FIG. 9 is a cross-sectional view taken along the line BB ′ shown in FIG. 7.

  The surface emitting semiconductor element of this embodiment is a surface emitting semiconductor laser element. This surface-emitting type semiconductor laser device includes a semiconductor active layer 4 having a light emitting region 13 on a normal substrate 1 having a plane orientation (100) plane, and a first semiconductor multilayer reflective film formed above the semiconductor active layer 4. A mirror 6 and a second semiconductor multilayer film reflecting mirror 2 formed below the semiconductor active layer 4 are provided. The semiconductor multilayer film reflecting mirror 2 and the semiconductor multilayer film reflecting mirror 6 form a resonator perpendicular to the main surface of the substrate 1. Semiconductor cladding layers 3 and 5 are provided between the semiconductor active layer 4 and the reflecting mirrors 2 and 6, respectively.

  Between the semiconductor multilayer film reflecting mirrors 6 and 2 and the cladding layers 5 and 3, an upper layer oxidized layer 32 and a lower layer oxidized layer 30 containing aluminum (Al) at a high concentration are provided. As will be described later, the semiconductor multilayer mirrors 6 and 2 also have an Al high concentration layer 6a containing Al at a high concentration. The semiconductor multilayer mirrors 6 and 2 and the oxidized layers 32 and 30 are oxidized regions 6b and 2b and oxidized regions 32a formed by selective oxidation laterally from the side wall of the mesa unit 100 toward the light emitting region 13. , 30a. These oxide regions 32a and 30a form a current confinement portion. The current 19 injected through the electrode 9 and the electrode 10 is narrowed down to the light emitting region 13 by this current constriction.

  A contact layer 7 is formed on the first semiconductor multilayer film reflecting mirror 6, and a contact electrode 9 for injecting a current into the light emitting region 13 is formed therethrough. The contact electrode 9 is formed so as to open on the light emitting region 13.

  An electrode 10 is formed on the back surface of the substrate 1, and a current is injected into the light emitting region 13 through the second semiconductor multilayer film reflecting mirror 2.

  In the direction of the A-A ′ line in FIG. 1, as shown in FIG. 2, an etching region (concave portion) 12 a is provided outside the mesa unit 100, and the etching region 12 a is embedded with a filler film 200. The depth of the etching region 12a is adjusted so that the side surfaces of the first semiconductor multilayer mirror 6, the upper layer oxidizable layer 32, and the cladding layer 5 are exposed, and the surface of the active layer 4 is exposed. The depth of the etching region 12a may be formed so as to reach at least the upper surface of the upper oxide layer 32. On the other hand, in the direction of the B-B ′ line in FIG. 1, as shown in FIG. 3, an etching region (concave portion) 12 b is provided outside the mesa unit 100. The etching region 12 b only needs to be formed so as to penetrate at least the lower layer to be oxidized 30. This etching region 12 b is buried with a filler film 200. The depth of the etching region 12b is such that the side surfaces of the first semiconductor multilayer reflector 6, the upper layer oxidizable layer 32, the clad layer 5, the active layer 4, the clad layer 3, and the lower oxidizable layer 30 are exposed. The side surfaces of a part of the layers of the semiconductor multilayer film reflecting mirror 2 are adjusted so that the side surfaces of some layers are exposed. As will be described in detail later, in this embodiment, the number of layers of the oxidized regions 32a and 30a is changed between the AA ′ line direction and the BB ′ line direction, and the shape of the oxidized region is changed. By embedding the filler film 200 in the recesses 12a and 12b having different depths, anisotropic stress is applied to the active layer 4 to realize high polarization controllability.

  Further, the peripheral portion 50 provided outside the etching regions 12 a and 12 b also has the same stacked structure as the mesa portion 100. A peripheral electrode 9 b is formed on the peripheral portion 50. The surface of the mesa unit 100 and the surface of the peripheral unit 50 are formed at substantially the same height.

  On the peripheral portion 50, a peripheral electrode 9b is formed. The contact electrode 9 and the peripheral electrode 9b are connected by a wiring path 18, and the peripheral electrode 9b and the bonding pad 17 are connected by a wiring portion 9a. A part of the wiring part 9 a is formed on the filler film 200. On the contact layer 7, a protective film 8 made of, for example, a silicon nitride film is appropriately provided.

  Such a surface emitting semiconductor laser can emit light by injecting current from the contact electrode 9 into the active layer 4 through the semiconductor multilayer reflector 6 as indicated by an arrow 19.

  This surface emitting semiconductor laser has a structure in which the contact electrode 9, the peripheral electrode 9 b, and the wiring path 18 connecting them are formed at substantially the same level (height) and does not require a flattening process. For this reason, there is an advantage that it is possible to prevent the “stage break” of the wiring.

  As described above, in this embodiment, the number of oxidized regions differs between the A-A ′ line direction and the B-B ′ line direction. That is, as shown in FIGS. 1 to 3, in the direction of the line AA ′, oxidized regions 6 b and 32 a are formed only in the first semiconductor multilayer film reflector 6 and the upper oxidized layer 32, while B In the −B ′ line direction, the first semiconductor multilayer film reflector 6, the upper layer oxidized layer 32, the lower layer oxidized layer 30, and a part of the second semiconductor multilayer film reflector 2, Oxidized regions 6b, 32a, 30a, and 2b are formed, respectively. That is, the number of layers in the oxidized region differs between the A-A ′ line direction and the B-B ′ line direction.

  Further, as shown in FIGS. 4 to 6, the surface-emitting type semiconductor laser device of this embodiment has an upper oxidizable layer 32 in the BB ′ line direction as an oxidized region for forming a current confinement portion, In the oxidized regions 32a and 30a of the lower oxidizable layer 30, the oxidized region 32a of only the upper oxidizable layer 32 is formed asymmetrically in the AA ′ line direction.

When a surface-emitting laser of a selective oxidation system is manufactured, AlAs (aluminum arsenic) or an AlGaAs (aluminum gallium arsenide) layer that is an oxidized layer containing Al at a high concentration (the composition ratio of Al in the group III element is 95). % Is preferable, the oxidized layers 32 and 30 or only the oxidized layer 32 are oxidized from the side wall of the mesa unit 100 to form a current confinement unit. Along with this, the compressive stress generated by the volume shrinkage accompanying the oxidation of the oxidized layers 32 and 30 greatly acts in the BB ′ line direction on the semiconductor active layer 4 at the center of the mesa portion 100. , Acting in the AA ′ line direction small. That is, strain is applied to the active layer 4 in an anisotropic manner. When the oxide layer Al _x (Ga) O _y is formed, volume shrinkage (about 10% to 13%) occurs as compared with the original Al (Ga) As layer. Therefore, after oxidation, the active layer 4 and the mesa structure A large compressive stress of the order of gigapascal (GPa) is applied to the center.

  Furthermore, in the present embodiment, the material of the filler film 200 embedded in the etching regions 12a and 12b is applied to the central portion of the semiconductor active layer 4 located at the center of the mesa portion 100 by using, for example, a polyimide resin or the like. The asymmetry of the compressive stress can be increased.

  When AlAs is used as the material of the oxidizable layers 32 and 30, the volume shrinkage due to the oxidation is 12% to 13%, so that a compressive stress F1 of 1 GPa to 10 GPa is generated per oxidizable layer. Therefore, since only the upper layer is in the AA ′ line direction, a compressive stress of F1 is generated, and in the BB ′ line direction, a compressive stress of 2 × F1 or more is generated in the upper and lower layers. The compressive stress applied depends on the direction.

Further, in order to effectively perform current squeezing, the oxidized layers 32 and 30 serving as current blocking layers need to have a certain thickness, but the larger the layer thickness or the greater the number of layers, The applied strain increases. In addition, the strain is concentrated at the tip of the oxidized region, and the oxidized layers 32 and 30 are provided at a close distance of about 0.2 μm from the active layer 4, so that the region where the current is most concentrated in the active layer 4. To affect. In this embodiment, the asymmetry of the stress application to the active layer 4 is increased, and the effect is higher than that in the prior art for improving the polarization controllability. In addition, when polyimide resin is used as the embedding material in the recess,
The thermal stress σ _T generated between the filler film 200 made of polyimide and the GaAs substrate 1 is expressed by the following equation.

_{σ T = E F (α F} -α S) ΔT

Here alpha _F is the thermal expansion coefficient of the polyimide, alpha _S is the thermal expansion coefficient of the GaAs substrate 1, _{E F} is the elastic modulus of the filler film 200 made of polyimide, [Delta] T is the temperature difference _{(T F} -T), T F polyimide The glass transition temperature, T, represents the measurement temperature.

When the glass transition temperature _TF is 300 ° C. and the operating temperature T is 20 ° C., ΔT = 280K, and at this time, a filler 200 made of polyimide (E _F = 3 GPa, α _F = 7 × 10 ⁻⁵ / K), In the GaAs substrate 1 (α _F = 6.0 × 10 ⁻⁶ / K), a compressive stress of σ _T = 54 MPa is generated. Thus, since the volume of the filler film 200 embedded in the recesses 12a and 12b varies depending on the location, the compressive stress is applied asymmetrically as well as the stress due to oxidation.

  In this embodiment, the depths of the recesses 12a and 12b are different, that is, the depth of the filler film 200 is different between the A-A ′ line direction and the B-B ′ line direction. For this reason, in this embodiment, the asymmetry of stress application to the active layer 4 is further increased as compared with the case of Patent Document 2 in which the planar shape varies depending on the direction but has the same depth. The polarization controllability can be further improved.

  Further, the conventional element structure for controlling polarization as shown in Patent Document 1 is a structure having a stress (strain) application region in the peripheral portion of the mesa. On the other hand, in this embodiment, the stress (strain) action region is at the center of the mesa unit 100 and has a structure closest to the semiconductor active layer 4. The stress applied to the semiconductor active layer decreases in inverse proportion to the distance between the stress (strain) application region and the active layer. For this reason, the polarization controllability becomes higher in the structure of the present embodiment located closest to the active layer than in the conventional case.

  Further, when there is a film stress in each layer grown on the substrate, the etching regions 12a and 12b for forming the mesa unit 100 have different recess etching volumes depending on the directions of AA ′ and BB ′. Accordingly, a compressive stress or a tensile stress is applied to the semiconductor active layer 4 asymmetrically in the horizontal direction with respect to the substrate surface, and the polarization controllability is further improved.

  In the surface-emitting type semiconductor laser device on the normal substrate, it is also possible to suppress the distortion of the shape of the current confinement portion due to the anisotropic oxidation that becomes remarkable in the inclined substrate in the selective oxidation.

  As described above, according to this embodiment, the polarization controllability is improved and a high-performance surface emitting semiconductor laser element can be obtained.

  For comparison, a comparative surface emitting semiconductor laser element having the structure shown in FIGS. 42 to 47 was manufactured. 42 is a top view of the comparative example, FIG. 43 is a cross-sectional view taken along the cutting line AA ′ shown in FIG. 42, and FIG. 44 is a cross-sectional view taken along the cutting line BB ′ shown in FIG. 45 is a diagram showing the shape of the oxidized region 32a of the upper oxidized layer 32 when the surface-emitting type semiconductor device of the comparative example is cut at a certain height 26, and FIG. 46 is a cut line AA ′ shown in FIG. FIG. 47 is a cross-sectional view taken along the cutting line BB ′ shown in FIG. 45.

  As shown in FIGS. 42 to 47, the surface-emitting type semiconductor laser device of this comparative example is the same as the surface-emitting type semiconductor laser device of the first embodiment except that the lower oxidized layer 30 is removed and the etching region (concave portion) 12a. 12b have the same cross-sectional size (size and depth), and the shape of the oxidized region 32a of the upper oxidized layer 32 is symmetrical regardless of the direction, that is, concentric.

  Thus, in the comparative example, the shape of the oxidized region 32a of the oxidized layer 32 is symmetric. For this reason, the compressive stress generated by the volume shrinkage accompanying the oxidation of the oxidized layer 32 is applied symmetrically to the central portion of the active layer 4 that is the center of the mesa portion 100, so that polarization control can be performed. Can not.

(Example)
Next, the method for manufacturing the surface-emitting type semiconductor laser according to the first embodiment will be specifically described as an example.

  First, an n-type semiconductor multilayer film reflector 2a, an electric current is formed on a cleaned 3-inch, 100-μm-thick n-type GaAs substrate 1 having a surface orientation (100) using a MOCVD (Metal Organic Chemical Vapor Deposition) apparatus. The oxidized layer 30a forming the constricted portion, the cladding layer 3, the semiconductor active layer 4, the cladding layer 5, the oxidized layer 32a forming the current confining portion, the p-type semiconductor multilayer reflector 6, and the contact layer 7 are grown in order. did.

  Here, a structure in which the semiconductor multilayer reflectors 2 and 6 are arranged above and below the resonator composed of the semiconductor active layer 4 and the clad layers 3 and 5 is considered as a basic structure, and a GaInAsN surface emitting semiconductor laser of 1.3 μm band. As a result, it was designed and manufactured to obtain the optimum performance.

The semiconductor multilayer mirror 2 has an n-type GaAs layer (high refractive index layer) and an n-type Al _y Ga _1-y As (0 <y <1) (thickness of optical wavelength 1/4 of wavelength 1.3 μm) ( Low refractive index layers) were alternately laminated. In this example, an Al _0.94 Ga _0.06 As layer having an Al composition and y = 0.94 was used as the low refractive index layer. In addition, Si was used as the n-type dopant of the semiconductor multilayer film reflecting mirror 2, and the dopant concentration was 2 × 10 ¹⁸ / cm ³ . The lower cladding layer 3 was n-type GaInP.

The semiconductor active layer 4 includes a Ga _x In _1-x As _y N _1-y (0 ≦ x ≦ 1, 0 ≦ y <1) layer adjusted to have an emission peak wavelength of 1.3 μm, and GaAs as a barrier layer. A quantum well structure in which layers were alternately stacked was used. Here, a Ga _x In _1-x As _y N _1-y (0 ≦ x ≦ 1, 0 ≦ y <1) layer is used as a center, and a three-layer structure in which a GaAs layer is stacked above and below it. The In composition of the Ga _x In _1-x As _y N _1-y (0 ≦ x ≦ 1, 0 ≦ y <1) layer that is the quantum well layer is 30% to 35%, and the nitrogen composition is 0.5% to 1 0.0% and thickness was 7 nm.

The lattice constant of the Ga _x In _1-x As _y N _1-y (0 ≦ x ≦ 1, 0 ≦ y <1) layer is controlled so as to be larger than that of the n-type GaAs substrate 1, and the compressive strain The composition was Ga _0.66 In _0.34 As _0.99 N _0.01 which contained an amount of about 2.5%. At this time, the differential gain coefficient increased, and the threshold current value was further reduced as compared with the case of no distortion.

The upper cladding layer 5 was p-type GaInP. The semiconductor multilayer mirror 6 has a p-type GaAs layer (high refractive index layer) and a p-type Al _y Ga _1-y As (0 <y <1) with a thickness of an optical wavelength of 1/4 of a wavelength of 1.3 μm. Low refractive index layers) were alternately laminated. Similar to the n-type semiconductor multilayer mirror 2, in this example, an Al _0.94 Ga _0.06 As layer having an Al composition and y = 0.94 was used as the low refractive index layer. Moreover, C (carbon) is used as the p-type dopant of the semiconductor multilayer mirror 6 and the dopant concentration is 2 × 10 ¹⁸ / cm ³ (near the quantum well layer 4) to 1 × 10 ¹⁹ / cm ³ (contact layer). 7).

The upper oxidizable layer 6a and the lower oxidizable layer 2a are formed on the cladding layer 5 and the cladding layer 3, respectively, and Al _x Ga having a larger Al composition ratio than AlGaAs constituting the upper and lower semiconductor multilayer reflectors 6 and 2. _1-x As (x ≧ 0.98) is used. In this example, an AlAs layer was used for both the upper and lower layers as the layer to be oxidized. The contact layer 7 is p-type GaAs, C (carbon) is used as the p-type dopant, and the dopant concentration is 2 × 10 ¹⁹ / cm ³ .

Next, an Si ₃ N ₄ film was formed as a protective film 8 that also served as an etching mask for pattern formation. The film stress was controlled by adjusting the pressure and flow rate of the source gas, SiH ₄ , NH ₃ , and N ₂ to form a film having a tensile stress of 150 MPa. The value of the tensile stress of the film was determined in consideration of the thermal stress σ _T generated between the etching mask 8 and the GaAs substrate 1 in the steam oxidation process. When the steam oxidation process temperature is set to 400 ° C., the Si ₃ N ₄ film (EF = 160 GPa, α _F = 2.7 × 10 ⁻⁷ / K) and the substrate GaAs (αS = 6.0 × 10 ⁻⁶ / K), a compressive stress of σ _T = −150 MPa is generated. In order to relieve the compressive stress, a film having a tensile stress is formed to increase the heat resistance.

  Next, etching was performed by photolithography and an etching process, and the mesa unit 100 was manufactured. The mesa pattern was etched with a boron trichloride / nitrogen mixed gas using an ICP (Inductively Coupled Plasma) plasma dry etching apparatus. At this time, as shown in FIGS. 1 to 3, the size of the opening of the etching region for forming the mesa is changed in the AA ′ line and BB ′ line directions (12a, 12b), and the area of the opening is changed. Using the so-called “microloading effect” in which the etching rate changes, mesa structures having different etching depths of recesses having different opening areas were produced.

Further, the mesa unit 100 is manufactured by adjusting the gas pressure, the antenna output, the bias output, and the substrate temperature. In the etching region 12a in the AA ′ line direction on the side wall of the mesa unit 100, the oxidized layer is formed. Only the upper oxidized layer 32 is exposed, and the upper and lower layers 32 and 30 of the oxidized layer are exposed in the etching region 12b in the BB ′ line direction. Here, the etching area for forming the mesa portion has an opening area of 1: 3 and an etching depth of 1: 2 in the direction of the AA ′ line and the BB ′ line. 1: 6. When crystal growth of a quantum well layer or the like made of Ga _x In _1-x As _y N _{1-y having} a large strain with respect to the substrate is performed as in this embodiment, each layer has a large film stress. Accordingly, since the etching volumes of the etching regions 12a and 12b formed when the mesa portion 100 is formed are different, a compressive stress or a tensile stress is applied to the semiconductor active layer 4 asymmetrically in the horizontal direction with respect to the substrate surface. This contributes to further improving the polarization controllability. Here, in order to fabricate a surface emitting semiconductor laser having an opening (current confinement portion) with a diameter of 5 μm, vertical etching with a mesa portion 100 having a diameter of 45 μm was performed.

  Next, a heat treatment at 400 ° C. is performed in a selective oxidation step and in a steam atmosphere, and the upper and lower oxidizable layers 32 and 30 are selectively oxidized in the lateral direction over a length of 20 μm to form oxidized regions 32a and 30a. The light emitting region 13 having a diameter of about 5 μm was formed.

At this time, the oxidized layers 32 and 30 are selectively oxidized in the lateral direction from the side wall of the mesa unit 100 toward the light emitting region 13, and the oxidized layers AlAs layers 32 and 30 become volumetric as they become Al ₂ O ₃ layers. Shrinkage occurs, and a compressive stress F _{1 of 1} GPa to ₁₀ GPa is generated per one layer to be oxidized, which is applied to the active layer 4 at the center of the mesa portion. At this time, since the AA ′ line direction is only the upper layer 32, it is F1, and since the BB ′ line direction is the upper layer 32 and the lower layer 30, it is 2 × F1. That is, since the compressive stress applied to the active layer 4 varies greatly depending on the direction, a gain difference between linearly polarized waves is generated in the active layer 4 and the polarization controllability is improved.

Next, the embedding process with the filler film material of the recesses 12a and 12b surrounding the mesa unit 100 was performed. Here, photosensitive polyimide resin was used as the filler film material. Using a spin coater, commercially available photosensitive polyimide resin CRC-8300 (manufactured by Sumitomo Bakelite Co., Ltd.) was spin-coated at a rotation speed of 2000 rpm for 30 seconds. Thereafter, baking was performed using a hot plate to form a 6 μm-thick photosensitive film. Next, pattern drawing (400 mJ / cm ² ) in which polyimide resin was embedded only in the recesses 12a and 12b was performed using a mask aligner exposure apparatus. After drawing, development processing was performed using a 2.38% aqueous solution of TMAH (Tetra-methyl ammonium hydroxide). Thereafter, a thermosetting treatment was performed in a nitrogen atmosphere at 150 ° C. for 30 minutes and at 320 ° C. for 30 minutes to form a filler film 200. Thereafter, oxygen plasma treatment (gas pressure: 0.7 Pa, flow rate: 100 sccm) with an antenna output of 500 W is performed in order to flatten the surfaces of the embedded portion and the peripheral portion and improve the adhesion with the metal (electrode material) to be deposited. I went for a minute.

  Subsequently, the etching mask film 8 on the p-type semiconductor multilayer film reflecting mirror 6 is removed, and a p-side electrode 9 is formed on the p-type GaAs contact layer 7. At this time, wirings 18 and 9a connecting the bonding pad 17 and the p-side electrode 9 were formed at the same time, and sintering was performed. Thereafter, the substrate is polished, and the film thicknesses of the electrode 9 and the wiring 18 are set to 100 μm. Finally, the n-side electrode 10 was formed on the back surface of the substrate.

In the surface-emitting type semiconductor laser fabricated in this manner, continuous oscillation at room temperature with a low threshold current density (1 kA / cm ² ) was achieved at a wavelength of 1.3 μm due to the effect of introducing compressive strain in the active layer 4. The laser characteristics were also good. In addition, polarization control becomes possible, and polarization fluctuations and switching do not occur. Along with this, noise is reduced, and it can be used as an optical disk head or a communication element.

  In addition, the distortion of the non-oxidized region caused by anisotropic oxidation on the inclined substrate and the shape of the outgoing beam pattern were improved, and a desired beam pattern shape was obtained. As a result, the transverse mode was stabilized. That is, for the purpose of comparison, when manufactured using the tilted substrate 1 tilted at an arbitrary angle, here 10 ° off from the (100) plane orientation substrate, which is effective for improving the polarization controllability, The shape distortion due to oxidation is remarkable, and in the same circular mesa structure as in this example, the shape of the opening (light emitting region 13) is distorted in the off direction as shown in FIG. As a result, a dimensional difference of 1.1 μm was produced in the vertical and horizontal directions. On the other hand, when a substrate having a plane orientation (100) plane is used, as shown in FIG. 40A, a symmetrical light emitting region 13 is obtained, and the vertical and horizontal dimensional difference is 0.1 μm. It was confirmed that it was reduced. In addition, the reproducibility over the entire surface is good, the dimensions and shapes of many elements formed on the same wafer are made uniform, and the laser characteristics such as single mode oscillation, threshold value, and optical output are made uniform. The mass productivity of high performance surface emitting semiconductor laser elements has been improved.

(First modification)
Next, a surface-emitting type semiconductor laser device according to a first modification of the first embodiment will be described with reference to FIGS. FIG. 10 is a diagram showing the shape of the oxidized region 32a of the upper oxidized layer 32 when the surface-emitting type semiconductor laser device of this modification is cut at a certain height 26, and FIG. 11 is a sectional line A-- shown in FIG. FIG. 12 is a cross-sectional view taken along the line BB ′ shown in FIG. 10.

  The surface-emitting type semiconductor laser device according to the first modification is the same as the surface-emitting type semiconductor laser device according to the first embodiment except that the lower oxidizable layer 30 is removed and the sizes (size and size) of the etching regions (recesses) 12a and 12b. The depth is changed, and the volume of the filler film 200 embedded therein is changed.

  Etching regions 12a and 12b in the A-A 'line and B-B' line directions have an opening area of 1: 4, an etching depth of 2: 3, and an etching volume of 1: 6. At this time, in the structure of this modified example, the oxidized layer has only symmetry in the AA ′ line direction and the BB ′ line direction as the oxidized region for forming the current confinement portion, and the oxidized layer has symmetry. The opening area and depth of the recesses are greatly different between the recesses 12a in the AA ′ line direction and the recesses 12b in the BB ′ line direction. For this reason, by using a polyimide resin as the material of the filler film 200, the compressive stress applied to the active layer 4 varies greatly between the direction and the upper and lower layers, and a gain difference between linearly polarized waves occurs in the semiconductor active layer 4, The polarization controllability has increased. Further, since the volume of the filler film 200 is different, a compressive stress is applied to the semiconductor active layer 4 asymmetrically in the horizontal direction with respect to the substrate surface, which contributes to further improving the polarization controllability. it is conceivable that.

  According to this modification, it is possible to obtain a surface emitting semiconductor laser device having high controllability of the polarization mode and high performance.

(Second modification)
Next, a surface-emitting type semiconductor laser device according to a second modification of the first embodiment will be described with reference to FIGS. FIG. 13 is a diagram showing the shape of the oxidized region of the upper oxide layer 32 when the surface emitting laser element according to this modification is cut at a certain height 26, and FIG. 14 is cut along the cutting line AA ′ shown in FIG. FIG. 15 is a cross-sectional view taken along the cutting line BB ′ shown in FIG.

  The surface emitting laser element of this modification is the same as the surface emitting laser element of the first embodiment except that the lower oxide layer 30 is deleted, the depths of the etching regions (recesses) 12a and 12b are the same, and the recesses 12b are formed. Is embedded in the filler film 200 but not in the recess 12a.

  As in the present modification, the stress difference applied to the active layer 4 depending on the presence or absence of the filler film 200 has a structure that differs greatly depending on the AA ′ line direction and the BB ′ line direction. A gain difference between linearly polarized waves occurs. Thereby, according to this modification, polarization controllability is enhanced.

  In the surface-emitting type laser device of the first embodiment shown in FIGS. 1 to 9, it is obvious that the polarization controllability can be similarly improved by using a structure in which the filler film 200 is not embedded in the recess 12a.

In the example of the first embodiment, the active layer 4 has been described using Ga _x In _1-x As _y N _1-y (0 ≦ x ≦ 1, 0 ≦ y <1). Various materials such as InGaAlP, AlGaAs, and InGaAsP can also be used.

  Various materials can also be used for the cladding layers 4 and 5 and the semiconductor multilayer reflectors 2 and 6. For example, the semiconductor multilayer mirrors 2 and 6 are not limited to the laminated structure of the AlGaAs layer and the GaAs layer, but may be a laminated structure of a material having a high refractive index and a small material that does not contain Al. A combination of GaInP / GaAs, GaInPAs / GaAs, GaInP / GaInAs, GaInP / GaPAs, GaInP / GaInAs, GaP / GaInAsN, and the like can be used.

  As the growth method, MBE (Molecular Beam Epitaxy) method or the like can also be used. In the above example, the example of the triple quantum well structure is shown as the stacked structure, but a structure using other quantum wells or the like can also be used.

  Further, in the present embodiment, the shape of the desired opening (light emitting region 13) has been described as being mainly circular. However, the same effect can be obtained even when the shape is a square, a rectangle, an ellipse, or the like. Needless to say, it can be done.

In this embodiment, AlAs layers are used as the oxidized layers 6a and 2a for forming the current confinement portion. However, Al _x Ga _1-x As (x ≧ 0.95) having a high Al composition ratio is used. It is clear that a similar effect can be obtained. When the Al composition ratio is high, in the steam oxidation process, the oxidation rate is fast, the process time can be shortened, and the amount of stress and strain generated by the oxidation is large. Is preferred.

  Moreover, although the case where the upper and lower oxidizable layers 32 and 30 are each one layer was demonstrated, the same effect can be acquired also when it is multiple layers. For example, if the upper layer of the layer to be oxidized is one layer and the lower layer is two layers, the asymmetry of the compressive stress applied to the semiconductor active layer 4 becomes more conspicuous than in the present embodiment. Can be increased.

In this embodiment, polyimide resin is used as the material of the filler film 200. However, the material is thermally expanded with the semiconductor material such as the substrate 1, the semiconductor multilayer reflectors 6 and 2, the oxidized layers 32 and 30, and the semiconductor active layer 4. It is clear that the same effect can be obtained by using other polymer materials or materials such as epoxy resins having greatly different coefficients. In addition to the polyimide resin, for example, an acrylic resin, an epoxy resin, or polysilane can be used as the material of the filler film 200.

(Second Embodiment)
Next, the configuration of a surface-emitting type semiconductor laser according to a second embodiment of the present invention will be described with reference to FIGS. 16 is a top view thereof, FIG. 17 is a sectional view taken along the cutting line AA ′ shown in FIG. 16, and FIG. 18 is a sectional view taken along the cutting line BB ′ shown in FIG. is there. FIG. 19 shows the shape of the oxidized region 6b of the semiconductor multilayer reflector 6 when the surface-emitting type semiconductor device of this embodiment is cut at a certain height 26, and the upper oxidized layer 32 when cut at a height 27. FIG. 20 is a cross-sectional view taken along the cutting line AA ′ shown in FIG. 19, and FIG. 21 is a cross-sectional view taken along the cutting line BB ′ shown in FIG. FIG. FIG. 22 shows the shape of the oxidized region 32a of the upper oxidizable layer 32 when the surface-emitting type semiconductor element of this embodiment is cut at a height 27, and the semiconductor multilayer reflector 2 when cut at a height 28. FIG. 23 is a cross-sectional view taken along the cutting line AA ′ shown in FIG. 22, and FIG. 24 is cut along the cutting line BB ′ shown in FIG. FIG.

  The surface-emitting type semiconductor laser device of this embodiment is the same as the surface-emitting type semiconductor laser device of the first embodiment shown in FIGS. 1 to 9, except that the lower oxidized layer 30 is removed and as shown in FIGS. In addition, the shape of the oxidized regions 6b and 2b of the semiconductor multilayer film is asymmetric, and the number of the Al high-concentration layers 2a and 6a to be oxidized of the semiconductor multilayer reflector differs depending on the location of the side wall of the mesa portion 100. It has become. When the difference in the number of Al high-concentration layers 2a and 6a to be oxidized in the semiconductor multilayer mirror is 10, a stress difference of the order of several tens of GPa is generated anisotropically. For this reason, the stress and strain applied to the semiconductor active layer 4 vary greatly depending on the direction, and since the structure acts at a position close to the active layer at the center of the mesa portion, the polarization controllability is high. Become. In addition, by using a polyimide resin or the like as a filler film material embedded in the recess around the mesa portion, stress (strain) increases and asymmetry can be increased, so that polarization controllability can be further improved. . Thereby, a surface-emitting type semiconductor laser device with high polarization controllability can be obtained as in the first embodiment.

  Next, a method for manufacturing the surface emitting semiconductor laser according to the present embodiment will be specifically described.

  First, an oxidized layer serving as an n-type semiconductor multilayer reflector 2 and a current confinement portion 14 is formed on a cleaned 3-inch, 400-μm-thick n-type GaAs substrate 1 having a plane orientation (100) using an MOCVD apparatus. 2a, the semiconductor clad layer 3, the semiconductor active layer 4, the semiconductor clad layer 5, the oxidized layer 6a to be the current confinement portion 14, the p-type semiconductor multilayer reflector 6 and the contact layer 7 are grown in this order.

  Here, a semiconductor multilayer reflectors 2 and 6 are disposed above and below a resonator composed of the semiconductor active layer 4, the semiconductor cladding layer 3 and the semiconductor cladding layer 5 as a basic structure, and a GaInAsN surface emitting semiconductor of 1.3 μm band. Designed and manufactured as a laser.

The semiconductor multilayer mirror 2 has an n-type GaAs layer (high refractive index layer) and an n-type Al _y Ga _1-y As (0 <y <1) (thickness of optical wavelength 1/4 of wavelength 1.3 μm) ( A low-refractive index layer) was alternately laminated. In the present embodiment, an Al _0.94 Ga _0.06 As layer having an Al composition and y = 0.94 was used as the low refractive index layer. In addition, Si was used as the n-type dopant of the semiconductor multilayer film reflecting mirror 2, and the dopant concentration was 2 × 10 ¹⁸ / cm ³ .

The semiconductor clad layer 3 was n-type GaInP. The semiconductor active layer 4 includes a Ga _x In _1-x As _y N _1-y (0 ≦ x ≦ 1, 0 ≦ y <1) layer adjusted to have an emission peak wavelength of 1.3 μm, and GaAs as a barrier layer. The quantum well structure was formed by laminating layers. Here, a Ga _x In _1-x As _y N _1-y (0 ≦ x ≦ 1, 0 ≦ y <1) layer is formed in the center, and a GaAs layer is formed as a barrier layer above and below this, did. Ga _x In _1-x As _y N _1-y (0 ≦ x ≦ 1, 0 ≦ y <1) The quantum well layer 4 has an In composition of 30% to 35% and a nitrogen composition of 0.5% to 1.0. %, And the thickness was 7 nm. The composition is controlled so that the lattice constant of the quantum well layer 4 made of Ga _x In _1-x As _y N _1-y (0 ≦ x ≦ 1, 0 ≦ y <1) is larger than that of the n-type GaAs substrate 1. Then, the composition Ga _0.66 In _0.34 As _0.99 N _0.01 containing an amount of compressive strain of about 2.5% was used. For this reason, the differential gain coefficient increased, and the threshold current value was further reduced as compared with the case of no distortion.

The semiconductor cladding layer 5 was p-type GaInP. The semiconductor multilayer mirror 6 has a p-type GaAs layer (high refractive index layer) and a p-type Al _y Ga _1-y As (0 <y <1) with a thickness of an optical wavelength of ¼ of a wavelength of 1.3 μm. A low-refractive index layer) was alternately laminated. Similar to the n-type semiconductor multilayer mirror 2, in the present embodiment, an Al _0.94 Ga _0.06 As layer having an Al composition and y = 0.94 was used as the low refractive index layer. Moreover, C (carbon) is used as a p-type dopant of the semiconductor multilayer film reflecting mirror 6, and the dopant concentration is 2 × 10 ¹⁸ / cm ³ (near the quantum well layer 4) to 1 × 10 ¹⁹ / cm ³ (contact layer). 7).

The oxidized layer 32 is formed on the cladding layer 5 and uses Al _x Ga _1-x As (x ≧ 0.98) having an Al composition ratio larger than that of AlGaAs constituting the upper and lower semiconductor multilayer reflectors 6 and 2. . In the present embodiment, an Al _0.98 Ga _0.02 As layer was used as the oxidized layer 32. The contact layer 7 was made of p-type GaAs, C (carbon) was used as the p-type dopant, and the dopant concentration was 2 × 10 ¹⁹ / cm ³ .

Next, a Si ₃ N ₄ film was formed in the same manner as in the example of the first embodiment as the protective film 8 also serving as an etching mask for pattern formation.

  Next, the n-type semiconductor multilayer film reflecting mirror 2 was etched by a photolithography process to form a mesa portion 100. The mesa pattern was etched with a boron trichloride / nitrogen mixed gas using an ICP (Inductively Coupled Plasma) plasma dry etching apparatus. At this time, by adjusting the antenna output, the bias output, and the substrate temperature, the conditions for anisotropic etching were set. Here, in order to manufacture a surface-emitting type semiconductor laser device in which the opening (current confinement portion) 14 has a circular shape of φ5 μm, the mesa was etched into a cylindrical shape having a diameter of 45 μm.

Next, heat treatment was performed at 420 ° C. in a steam atmosphere, and the oxidized layer 32 was selectively oxidized in the lateral direction to form an oxidized region 32a. The formation of the oxidized region 32a by steam selective oxidation was performed by heat treatment at 420 ° C. At a substrate temperature of 420 ° C., the oxidation rate of the Al _0.94 Ga _0.06 As layer used for the Al high-concentration layers 6 a and 2 a of the semiconductor multilayer reflectors 6 and 2 is such that the Al _0.98 Ga of the layer 32 to be oxidized. _In this example, the oxidation length of the oxidized layer 32 is set to 20 μm in order to form the oxidized region 32a. Therefore, the Al of the semiconductor multilayer reflectors 6 and 2 is formed. The oxidation length in the horizontal direction of the high concentration layers 6a and 2a is 5 μm. At this time, as the etching depth for forming the mesa portion is different, asymmetry is generated in the compressive stress applied to the active layer at the center of the mesa portion 100. Volume shrinkage due to oxidation of the Al _0.94 Ga _0.06 As layer, which is the Al high concentration layer 6 a of the semiconductor multilayer mirror 6, is 7.5% to 8.5%. For this reason, on the side walls of the recesses 12a and 12b having different etching depths, if the difference in the number of Al high-concentration layers to be oxidized of the semiconductor multilayer reflector is 10, stress on the order of several tens of GPa is generated. In addition, the magnitude of stress and strain applied to the active layer varies greatly depending on the direction. The stress generated per layer is smaller than that of the oxidized layer 32 containing Al at a higher concentration, and the distance from the active layer at the center of the mesa is far, but the difference in the number of oxidized Al high concentration layers is large. For example, the total stress increases, and the same polarization controllability and shape controllability can be obtained. Moreover, it was shown that the distortion of the shape (a dimensional difference of 0.75 μm in the vertical and horizontal directions) generated in the off-angle direction is reduced to 0.1 μm in the inclined substrate.

  Next, a buried filler film 200 is formed only in the recesses 12a and 12b surrounding the mesa unit 100 using a photosensitive polyimide resin. Next, a bonding pad 17 was formed. Next, the protective film 8 on the p-type semiconductor multilayer reflective mirror 6 serving as a light extraction port is removed, and a p-side electrode 9 is formed on the p-type GaAs contact layer 7. At this time, wirings 18 and 9a connecting the bonding pad 17 and the p-side electrode 9 were formed at the same time, and then the n-side electrode 10 was formed on the back surface of the substrate.

  The surface-type semiconductor laser device manufactured in this way has a low threshold current density and single-mode room-temperature continuous oscillation at a wavelength of 1.3 μm due to the effect of introducing compressive strain in the active layer 4 at a high temperature. The characteristics were also good. In addition, polarization control becomes possible, and polarization fluctuations and switching do not occur. Along with this, noise is reduced, and it can be used as an optical disk head or a communication element.

  Further, as in the first embodiment, the non-oxidized region generated by anisotropic oxidation and the size and shape of the outgoing beam pattern were improved, and the desired beam pattern size and shape were obtained.

In this embodiment, the active layer 4 has been described using Ga _x In _1-x As _y N _1-y (0 ≦ x ≦ 1, 0 ≦ y <1). However, the present invention is not limited thereto, and the InGaAlP-based, AlGaAs Various materials such as a system and an InGaAsP system can also be used. The cladding layers 4 and 5 and the semiconductor multilayer reflectors 2 and 6 can also be made of various materials. For example, the semiconductor multilayer mirrors 2 and 6 are not limited to the laminated structure of the AlGaAs layer and the GaAs layer, but may be a laminated structure of a material having a high refractive index and a small material that does not contain Al. A combination of GaInP / GaAs, GaInPAs / GaAs, GaInP / GaInAs, GaInP / GaPAs, GaInP / GaInAs, GaP / GaInAsN, and the like can be used.

  As a growth method, an MBE method or the like can also be used. In the above example, the example of the triple quantum well structure is shown as the stacked structure, but a structure using other quantum wells or the like can also be used.

  Moreover, although the case where the upper and lower oxidized layers 32 are one layer was demonstrated, the same effect can be acquired also when it is multiple layers.

  In addition, in the present embodiment, the shape of the desired opening (light emitting region 13) is a circular shape, but it is obvious that the same effect can be obtained even if a shape such as a square, a rectangle, or an ellipse is used. is there.

In the present embodiment, an Al _0.98 Ga _0.02 As layer is used as the oxidized layer 32 for forming the current confinement portion. However, an Al As layer and an Al _x Ga _1-x As having a low Al composition ratio are used. It is clear that the same effect can be obtained even when (x ≧ 0.95) is used.

(Third embodiment)
Next, the structure of a surface emitting semiconductor laser according to a third embodiment of the invention will be described with reference to FIGS. 25 is a top view thereof, FIG. 26 is a cross-sectional view taken along the cutting line AA ′ shown in FIG. 25, and FIG. 27 is a cross-sectional view taken along the cutting line BB ′ shown in FIG. is there. FIG. 28 shows the shape of the oxidized region 6b of the semiconductor multilayer reflector 6 when the surface-emitting type semiconductor device of this embodiment is cut at a certain height 26, and the upper oxidized layer 32 when cut at a height 27. FIG. 29 is a cross-sectional view taken along the cutting line AA ′ shown in FIG. 28, and FIG. 30 is cut along the cutting line BB ′ shown in FIG. FIG.

  The surface-emitting type semiconductor laser device of this embodiment is the same as the surface-emitting type semiconductor laser device of the first embodiment shown in FIGS. 1 to 9, except that the lower oxidized layer 30 is removed and the first semiconductor multilayer mirror is used. 6 is provided with a proton injection region 15 for controlling the oxidation rate.

In the Al high concentration layer 6a composing the first semiconductor multilayer film reflecting mirror 6 provided with the proton injection region 15, the oxidation rate of steam oxidation is greatly reduced in proportion to the proton concentration as shown in FIG. To do. For this reason, in the proton injection region 15, the oxidation length from the side surfaces of the recesses 12a and 12b is short, and the stress is higher than that of the Al high concentration layer 6a of the semiconductor multilayer reflector having a long oxidation length (no proton injection). Application of strain applied to the semiconductor active layer 4 at the center of the mesa portion is anisotropic (asymmetric). Therefore, the surface-emitting type semiconductor laser device of this embodiment can improve the polarization controllability and obtain high performance as in the first to second embodiments. Further, as will be described later, the fabrication is easy, and the mass productivity of the surface emitting semiconductor laser element is improved.

  Next, a method for manufacturing the surface-emitting type semiconductor laser device of this embodiment will be specifically described.

First, an n-type semiconductor multilayer mirror 2, a semiconductor clad layer 3, and a semiconductor active layer 4 are formed on an n-type GaAs substrate 1 having a thickness of 400 μm and a surface orientation (100) of 100 μm using a MOCVD apparatus. Then, the semiconductor clad layer 5, the oxidized layer 32 serving as a current confinement portion, the p-type semiconductor multilayer film reflecting mirror 6, and the contact layer 7 are sequentially grown.

  Here, a semiconductor multilayer reflectors 2 and 6 are disposed above and below a resonator composed of the semiconductor active layer 4, the semiconductor cladding layer 3 and the semiconductor cladding layer 5 as a basic structure, and a GaInAsN surface emitting semiconductor of 1.3 μm band. Designed and manufactured as a laser.

The semiconductor multilayer mirror 2 has an n-type GaAs layer (high refractive index layer) and an n-type Al _y Ga _1-y As (0 <y <1) (thickness of optical wavelength 1/4 of wavelength 1.3 μm) ( A low-refractive index layer) was alternately laminated. In the present embodiment, an Al _0.94 Ga _0.06 As layer having an Al composition and y = 0.94 was used as the low refractive index layer. In addition, Si was used as the n-type dopant of the semiconductor multilayer film reflecting mirror 2, and the dopant concentration was 2 × 10 ¹⁸ / cm ³ .

N-type GaInP was used as the material of the semiconductor cladding layer 3. The semiconductor active layer 4 includes a Ga _x In _1-x As _y N _1-y (0 ≦ x ≦ 1, 0 ≦ y <1) layer adjusted to have an emission peak wavelength of 1.3 μm, and GaAs as a barrier layer. The quantum well structure was formed by laminating layers. Here, a Ga _x In _1-x As _y N _1-y (0 ≦ x ≦ 1, 0 ≦ y <1) layer is formed in the center, and a GaAs layer is formed as a barrier layer above and below this, did. Ga _x In _1-x As _y N _1-y (0 ≦ x ≦ 1, 0 ≦ y <1) The quantum well layer 4 has an In composition of 30% to 35% and a nitrogen composition of 0.5% to 1.0. %, And the thickness was 7 nm. The composition is controlled so that the lattice constant of the quantum well layer 4 made of Ga _x In _1-x As _y N _1-y (0 ≦ x ≦ 1, 0 ≦ y <1) is larger than that of the n-type GaAs substrate 1. Then, the composition Ga _0.66 In _0.34 As _0.99 N _0.01 containing an amount of compressive strain of about 2.5% was used. For this reason, the differential gain coefficient increased, and the threshold current value was further reduced as compared with the case of no distortion.

The semiconductor cladding layer 5 was p-type GaInP. The semiconductor multilayer mirror 6 has a p-type GaAs layer (high refractive index layer) and a p-type Al _y Ga _1-y As (0 <y <1) with a thickness of an optical wavelength of ¼ of a wavelength of 1.3 μm. A low-refractive index layer) was alternately laminated. Similar to the n-type semiconductor multilayer mirror 2, in the present embodiment, an Al _0.94 Ga _0.06 As layer having an Al composition and y = 0.94 was used as the low refractive index layer. Further, as a p-type dopant in the semiconductor multilayer reflection mirror 6, using the C (carbon), the dopant concentration is, 2 × ¹⁰¹⁸ / cm ³ (near quantum well layer ^{4) ~1 × 10 19 / cm} 3 ( the contact layer 7 Neighborhood).

The upper oxidizable layer 32 is formed on the cladding layer 5 and below the cladding layer 3, respectively, and Al _x Ga _1-x As (x having a larger Al composition ratio than the AlGaAs constituting the upper and lower semiconductor multilayer reflectors 6 and 2. ≧ 0.98) is used. In this example, an Al _x Ga _1-x As (x = 0.98) layer was used. The contact layer 7 was made of p-type GaAs, C (carbon) was used as the p-type dopant, and the dopant concentration was 2 × 10 ¹⁹ / cm ³ .

Next, a Si ₃ N ₄ film was formed as a protective film 8 also serving as an etching mask for forming a mesa pattern using a photolithography process. Subsequently, the proton implantation region 15 was formed using the protective film 8 and the resist pattern (not shown) used when patterning the protective film 8 as a mask. Then, ion implantation was performed with an ion implantation apparatus on the Al high concentration layer 6a of the semiconductor multilayer film reflecting mirror 6 under the conditions of an acceleration voltage of 200 keV and a dose of 3 × 10 ¹³ / cm ² . The proton injection region 15 formed at this time has a depth of 1.5 μm from the surface and a maximum concentration of 1 × 10 ¹⁸ / cm ³ , and a concentration in a portion of 1 μm to 2 μm deep from the surface is 1 × 10 ¹⁶ / cm ^3. This is the region as described above. In addition, protons are not injected into the Al _0.98 Ga _0.02 As layer (depth of 2.6 μm from the surface) of the oxidized layer 32. Also, under this condition, the implantation region has a concentration that does not increase the resistance. As can be seen from the proton concentration dependence of the oxidation rate of the AlGaAs layer shown in FIG. 41, at a proton concentration of 1 × 10 ¹⁷ / cm ³ , the oxidation rate decreases to about ３. Therefore, the high-concentration Al layer 6a of the semiconductor multilayer reflector 6 into which protons have been implanted has a significantly reduced oxidation rate in the steam oxidation process, and the oxidation length can be reduced to about 1/3, and the element resistance does not increase.

  Next, a mesa formation pattern is formed on the protective film 8 with a resist, and the mesa portion 100 is etched to the upper portion of the n-type semiconductor multilayer mirror 2 by a photolithography process using the mesa formation pattern as a mask. Make it. The mesa pattern was etched with a boron trichloride / nitrogen mixed gas using an ICP (Inductively Coupled Plasma) plasma dry etching apparatus. At this time, by adjusting the antenna output, the bias output, and the substrate temperature, the conditions for anisotropic etching were set. Here, in order to manufacture a surface emitting semiconductor laser having an opening (light emitting region 13) having a circular shape with a diameter of 5 μm, the mesa portion 100 was etched so as to have a cylindrical shape with a diameter of 45 μm.

Next, heat treatment was performed at 420 ° C. in a water vapor atmosphere to selectively oxidize the oxidized layer 32 in the lateral direction, thereby forming an oxidized region 32a serving as a current confinement portion. At a substrate temperature of 420 ° C. (with no proton injection), the oxidation rate of the Al _0.94 Ga _0.06 As layer, which is the Al high-concentration layer 6 a of the semiconductor multilayer reflector 6, is Al _0.98 Ga, which is the layer to be oxidized. _0.02 About 1/4 of the As layer. Here, since the oxidation length of the oxidized layer 32 is set to 20 μm for the formation of the oxidized region 32a, the lateral direction of the Al high concentration layer 6a of the semiconductor multilayer film reflecting mirror 6 in the portion where protons are not implanted is set. The oxidation length becomes 5 μm. In the proton injection region 15, this is as short as about 1/3 of 1.7 μm, and asymmetry is generated in the compressive stress applied to the active layer 4 at the center of the mesa portion 100. Volume shrinkage due to oxidation of the Al _0.94 Ga _0.06 As layer, which is the Al high concentration layer 6a of the semiconductor multilayer reflector 6, is 7.5% to 8.5%, and a semiconductor multilayer into which protons are injected. If the number of layers of the film reflector is 10, a stress of several tens of GPa is generated as a whole, and the stress and strain applied to the active layer 4 are the distance between the center of the active layer 4 and the oxidized layer 32. Therefore, the compressive stress applied to the active layer 4 varies greatly depending on the direction. When the oxidation length from the side surface is 20 μm and the non-oxidation (light emission) region 13 having a diameter of 5 μm is produced, the distortion of the shape generated in the off-angle direction in the inclined substrate (10 ° off) (vertical and horizontal 0.75 μm) It has been shown that the dimensional difference is reduced to 0.1 μm in the normal substrate (100).

  Next, a filler film material (for example, polyimide resin) was embedded in the recesses 12a and 12b surrounding the mesa unit 100 using a photosensitive polyimide resin to form a filler film 200. Next, a bonding pad 17 was formed. Next, the protective film 8 on the p-type semiconductor multilayer reflective mirror 6 serving as a light extraction port is removed, and a p-side electrode 9 is formed on the p-type GaAs contact layer 7. At this time, wirings 18 and 9a connecting the bonding pad 17 and the p-side electrode 9 were formed at the same time, and then the n-side electrode 10 was formed on the back surface of the substrate.

  In the surface type semiconductor laser fabricated in this way, in addition to the effect of introducing compressive strain in the active layer 4 at a wavelength of 1.3 μm, the leakage current is prevented and reduced by the high resistance by proton injection under the wiring path. Threshold current density, single mode continuous oscillation at room temperature were obtained, and the characteristics at high temperature were good. In addition, polarization control becomes possible, and polarization fluctuations and switching do not occur. Along with this, noise is reduced, and it can be used as an optical disk head or a communication element.

Here, the case where the layer to be oxidized 32 is a single layer has been described in the present embodiment, but the same effect can be obtained when the layer is a plurality of layers. In addition, instead of the oxidized layer 32, an Al _x Ga _1-x having an Al composition ratio larger than that of AlGaAs constituting the semiconductor multilayer reflective mirror 2 between the cladding layer 3 and the semiconductor multilayer reflective mirror 2 as an oxidized layer. As (x ≧ 0.95) may be provided. That is, the oxidized layer 30 of the first embodiment shown in FIGS. 1 to 9 is provided. In this case, since the layer to be oxidized is located deeper than the surface, there is an advantage that it is hardly affected by proton implantation.

(Fourth embodiment)
Next, the structure of a surface emitting semiconductor laser according to a fourth embodiment of the present invention will be described with reference to FIGS. 31 is a top view thereof, FIG. 32 is a sectional view taken along the cutting line AA ′ shown in FIG. 31, and FIG. 33 is a sectional view taken along the cutting line BB ′ shown in FIG. is there. FIG. 34 shows the shape of the oxidized region 6b of the semiconductor multilayer reflector 6 when the surface-emitting type semiconductor device of this embodiment is cut at a certain height 26, and the upper layer oxidizable layer 32 when cut at a height 27. FIG. 35 is a cross-sectional view taken along the cutting line AA ′ shown in FIG. 34, and FIG. 36 is cut along the cutting line BB ′ shown in FIG. FIG. FIG. 37 shows the shape of the oxidized region 30a of the lower layer to be oxidized 30 when the surface-emitting type semiconductor device of this embodiment is cut at a height 28, and the semiconductor multilayer reflector 2 when cut at a height 29. FIG. 38 is a cross-sectional view taken along the cutting line AA ′ shown in FIG. 37, and FIG. 39 is cut along the cutting line BB ′ shown in FIG. FIG.

  The surface-emitting type semiconductor laser device of the present embodiment is different from the surface-emitting type semiconductor laser device of the first embodiment shown in FIGS. 1 to 9 in that the depths of the recesses 12a and 12b are made deeper but different. Only the first semiconductor multilayer mirror 6 in the AA ′ line direction is provided with a proton injection region 15 for controlling the oxidation rate. As a result, the oxidation rate of the Al high-concentration layer 6a and the oxidized layer 32 constituting the first semiconductor multilayer mirror 6 in the proton injection region 15 is greatly reduced in proportion to the proton concentration in the steam oxidation. . In the proton implantation region 15, the oxidation length from the side surface of the recess is short, and the strain applied to the semiconductor active layer 4 at the center of the mesa portion is anisotropic (asymmetric). Here, all three of the oxidized region 6b of the Al high concentration layer 6a, the oxidized region 32a of the upper layer to be oxidized layer 32, and the filler film 200 of the first semiconductor multilayer mirror 6 have asymmetric properties. It has a structure in which high stress is applied. For this reason, very high selectivity with a polarization extinction ratio of 20 dB or more was obtained, and laser characteristics with excellent polarization controllability were obtained.

  As the current confinement structure, the oxidized layer 32 has an oxidized shape that spreads in the AA ′ line direction as shown in FIGS. 34 to 36, but the lower oxidized layer 30 in which the proton implantation region 15 is not formed. In the structure, a desired narrowed shape can be obtained.

In the present embodiment, Ga _x In _1-x As _y N _1-y (0 ≦ x ≦ 1, 0 ≦ y <1) is used as the active layer 4. However, the present invention is not limited to this, and InGaAlP, AlGaAs, Various materials such as InGaAsP can also be used.

  The cladding layers 4 and 5 and the semiconductor multilayer reflectors 2 and 6 can also be made of various materials. For example, the semiconductor multilayer mirrors 2 and 6 are not limited to the laminated structure of the AlGaAs layer and the GaAs layer, but may be a laminated structure of a material having a high refractive index and a small material that does not contain Al. A combination of GaInP / GaAs, GaInPAs / GaAs, GaInP / GaInAs, GaInP / GaPAs, GaInP / GaInAs, GaP / GaInAsN, and the like can be used.

  As a growth method, an MBE method or the like can also be used. In the above example, the example of the triple quantum well structure is shown as the stacked structure, but a structure using other quantum wells or the like can also be used.

  In addition, in the present embodiment, the shape of the desired opening (light emitting region 13) is a circular shape, but it is obvious that the same effect can be obtained even if a shape such as a square, a rectangle, or an ellipse is used. is there.

Further, in the present embodiment, 1 × 10 ¹⁷ / cm ³ is used as the proton concentration to be injected. However, it is obvious that the same effect can be obtained even if protons having a concentration higher or lower than this concentration are used. is there. When high concentration protons are injected, the oxidation rate of the Al high concentration layer 6a of the semiconductor multilayer mirror 6 containing Al at a high concentration is greatly reduced, and the progress of oxidation can be suppressed at a desired position. This is preferable because the controllability of the oxidized shape is enhanced. On the other hand, when protons are injected at a higher concentration than the dopant concentration of the semiconductor multilayer reflectors 2 and 6, the proton injection region has a high resistance and current does not flow easily. Easy to flow. For this reason, it is necessary to devise the positions of the proton injection region and the upper electrode so that the current is narrowed down to the non-oxidized region. The concentration of protons injected into the proton injection region 15 is preferably 1 × 10 ¹⁸ / cm ³ or less.

In this embodiment, an Al _0.98 Ga _0.02 As layer is used as the oxidized layer 32 for forming the current confinement portion. However, an AlAs layer having a high Al composition ratio or an Al _x Ga _1-x As ( It is clear that the same effect can be obtained by using x ≧ 0.95).

  As described above, according to each embodiment of the present invention, a high-performance surface-emitting semiconductor element having high polarization controllability and mass productivity even when manufactured on a normal substrate such as a plane orientation (100) plane Can be obtained.

1 is a top view of a surface-emitting type semiconductor device according to a first embodiment of the present invention. Sectional drawing when it cut | disconnects by the cutting line A-A 'shown in FIG. Sectional drawing when it cut | disconnects by the cutting line B-B 'shown in FIG. The figure which shows the shape of the oxidation area | region 32a of the upper layer to-be-oxidized layer 32 when the surface emitting semiconductor element of 1st Embodiment is cut | disconnected by the certain height 26. FIG. Sectional drawing when it cut | disconnects by the cutting line A-A 'shown in FIG. Sectional drawing when it cut | disconnects by the cutting line B-B 'shown in FIG. The figure which shows the shape of the oxidation area | region of the lower layer to-be-oxidized layer 30 when the surface emitting semiconductor element of 1st Embodiment is cut | disconnected by other height 27. FIG. Sectional drawing when it cut | disconnects by the cutting line A-A 'shown in FIG. Sectional drawing when it cut | disconnects by the cutting line B-B 'shown in FIG. The figure which shows the shape of the oxidation area | region 32a of the upper layer to-be-oxidized layer 32 when the surface emitting semiconductor laser element by the 1st modification of 1st Embodiment is cut | disconnected by the certain height 26. FIG. Sectional drawing when it cut | disconnects by the cutting line A-A 'shown in FIG. Sectional drawing when it cut | disconnects by the cutting line B-B 'shown in FIG. The figure which shows the shape of the oxidation area | region of the upper-layer oxide layer 32 when the surface emitting laser element by the 2nd modification of 1st Embodiment is cut | disconnected by the certain height 26. FIG. Sectional drawing when it cut | disconnects by the cutting line A-A 'shown in FIG. Sectional drawing when it cut | disconnects by the cutting line B-B 'shown in FIG. The top view of the surface emitting semiconductor laser by 2nd Embodiment of this invention. Sectional drawing when it cut | disconnects by the cutting line A-A 'shown in FIG. FIG. 17 is a cross-sectional view taken along the cutting line B-B ′ shown in FIG. 16. The shape of the oxidized region 6b of the semiconductor multilayer reflector 6 when the surface-emitting type semiconductor device of the second embodiment is cut at a certain height 26, and the oxidized region of the upper oxidized layer 32 when cut at a height 27 The figure which accumulated and showed the shape of 32a, respectively. Sectional drawing when it cut | disconnects by the cutting line A-A 'shown in FIG. Sectional drawing when it cut | disconnects by the cutting line B-B 'shown in FIG. The shape of the oxidized region 32a of the upper layer 32 to be oxidized when the surface-emitting type semiconductor device of the second embodiment is cut at a height 27, and the oxidized region 2b of the semiconductor multilayer mirror 2 when cut at a height 28 The figure which accumulated and showed the shape of. FIG. 23 is a cross-sectional view taken along the cutting line A-A ′ shown in FIG. 22. FIG. 23 is a cross-sectional view taken along the cutting line B-B ′ shown in FIG. 22. The top view of the surface emitting semiconductor laser by 3rd Embodiment of this invention. FIG. 26 is a cross-sectional view taken along the cutting line A-A ′ shown in FIG. 25. FIG. 26 is a cross-sectional view taken along the cutting line B-B ′ shown in FIG. 25. The shape of the oxidized region 6b of the semiconductor multilayer reflector 6 when the surface-emitting type semiconductor device of the third embodiment is cut at a certain height 26, and the oxidized region of the upper oxidized layer 32 when cut at a height 27 The figure which accumulated and showed the shape of 32a, respectively. FIG. 29 is a cross-sectional view taken along the cutting line A-A ′ shown in FIG. 28. FIG. 29 is a cross-sectional view taken along the cutting line B-B ′ shown in FIG. 28. The top view of the surface emitting semiconductor laser by 4th Embodiment of this invention. Sectional drawing when it cut | disconnects by the cutting line A-A 'shown in FIG. Sectional drawing when it cut | disconnects by the cutting line B-B 'shown in FIG. The shape of the oxidized region 6b of the semiconductor multilayer film reflecting mirror 6 when the surface-emitting type semiconductor element of the fourth embodiment is cut at a certain height 26, and the oxidation of the upper oxidized layer 32 when cut at the height 27 The figure which showed the shape of field 32a in piles. Sectional drawing when it cut | disconnects by the cutting line A-A 'shown in FIG. Sectional drawing when it cut | disconnects by the cutting line B-B 'shown in FIG. The shape of the oxidized region 30a of the lower layer to be oxidized 30 when the surface-emitting type semiconductor device of the fourth embodiment is cut at a height 28 and the oxidized region 2b of the semiconductor multilayer reflector 2 when cut at a height 29 The figure which accumulated and showed the shape of. Sectional drawing when it cut | disconnects by the cutting line A-A 'shown in FIG. Sectional drawing when it cut | disconnects by the cutting line B-B 'shown in FIG. The schematic diagram which shows the shape of the non-oxidized area | region in a (100) plane board | substrate and a 10 degrees off board | substrate. The graph which shows the dependence with respect to the proton concentration of the oxidation rate of an AlGaAs layer. The top view of the surface emitting semiconductor laser element by the comparative example of 1st Embodiment. FIG. 43 is a cross-sectional view taken along the cutting line A-A ′ shown in FIG. 42. Sectional drawing when it cut | disconnects by the cutting line B-B 'shown in FIG. The figure which shows the shape of the oxidation area | region 32a of the upper layer to-be-oxidized layer 32 when the surface emitting semiconductor element of a comparative example is cut | disconnected by the certain height 26. FIG. FIG. 46 is a cross-sectional view taken along the cutting line A-A ′ shown in FIG. 45. FIG. 46 is a cross-sectional view taken along the cutting line B-B ′ shown in FIG. 45.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 2 Semiconductor multilayer reflective film 2a Oxidation area | region 3 Clad layer 4 Semiconductor active layer 5 Clad layer 6 Semiconductor multilayer reflective film 6a High concentration layer 6b of semiconductor multilayer reflector oxidization area 7 Contact layer 8 Protective film 9 P side electrode 9a Wiring portion 9b Peripheral electrode 10 N-side electrode 12a Etching region (concave portion)
12b Etching region (concave)
13 Light emitting region 15 Proton injection region 17 Bonding pad 18 Wiring path 19 Injection current 30 Lower layer oxidizable layer 32 Upper layer oxidizable layer 50 Peripheral portion 100 Mesa portion 200 Filler film

Claims (10)

A substrate,
A semiconductor active layer having a light emitting region formed on the substrate;
Sandwiching the semiconductor active layer to form a resonator perpendicular to the substrate;
A first semiconductor multilayer reflector formed on the opposite side of the substrate with respect to the semiconductor active layer, and a second semiconductor multilayer reflector formed on the substrate side with respect to the semiconductor active layer;
A pair of electrodes for injecting current into the semiconductor active layer;
A current confinement portion formed in the vicinity of the semiconductor active layer, having a first oxidizable layer containing Al, wherein a side portion of the first oxidizable layer is oxidized and a central portion is unoxidized;
A first recess having a groove depth reaching at least the outermost surface layer of the first oxidizable layer;
A second recess penetrating the first oxidizable layer;
A mesa portion surrounded by the first and second recesses;
An insulating film embedded in at least the second recess of the first and second recesses;
With
The first oxidized layer of the current confinement portion is characterized in that the size of the oxidized region is different between the direction in which the first recess is provided and the direction in which the second recess is provided. Surface-emitting semiconductor element.   2. The surface emitting semiconductor element according to claim 1, wherein the insulating film is also embedded in the first recess.   3. The surface-emitting type semiconductor device according to claim 1, wherein the first oxidized layer is formed on the substrate side with respect to the semiconductor active layer.   3. The surface-emitting type semiconductor device according to claim 1, wherein the first oxidized layer is formed on a side opposite to the substrate with respect to the semiconductor active layer.   5. The surface-emitting type semiconductor device according to claim 4, wherein the current confinement portion includes a second oxidized layer that is formed on the substrate side with respect to the semiconductor active layer and contains Al.   6. The surface-emitting type semiconductor device according to claim 5, wherein the second oxidized layer has an unoxidized central portion and oxidized side portions.   The surface emitting semiconductor device according to claim 1, wherein the mesa portion includes a proton injection region in the first semiconductor multilayer film reflecting mirror.   The insulating film is made of a material having a thermal expansion coefficient larger than that of the substrate, the first and second semiconductor multilayer mirrors, and the semiconductor active layer. A surface-emitting type semiconductor device as described in 1.   The surface-emitting type semiconductor element according to claim 1, wherein the insulating film is made of a polyimide resin.   10. The surface emitting semiconductor element according to claim 1, wherein the semiconductor active layer is made of a semiconductor containing at least Ga, In, and one of As or N.

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